Electrolytic condenser and method of making the same



Feb. 18, 1936. A. RAINES 2,031,128

ELECTROLYTIC CONDENSER AND METHOD OF MAKING THE SAME Filed July 19, 1953 INVENTOR AR/Vow Rmzvzs fl 'ATTORNE 5 Patented Feb. 18, 1936 ELECTROLYTIC CONDENSER OFMAKIN AND METHOD GTHE SAME Arnold Raines, Brooklyn, N. Y.

Application July 19, 1933, Serial No. 681,086

12, Claims.

My present invention relates to electrolytic condensers, and methods of manufacturethereof, and aims to devise a condenser of the general character specified which will be of cheaper construction than those heretofore known, and which will work at increased efficiency. Other objects and advantages of the present invention, such as simplicity, will become apparent from the embodiment of the invention shown by way of example in the accompanying drawing, in which Fig. 1 shows a flat plate condenser cut away in part to show the electrolytic fluid and separating means, and Fig. 2 shows the device in coiled form.

Before describing in detail the elements of my present invention I wish to make a brief analysis of the prior art, from which can be seen the superiorities of my present invention. Heretofore, an electrolytic condenser has been manufactured by coating 9. thin strip of aluminum with a fine layer of aluminum oxide, which acts as a dielectric. Between this strip of aluminum and another strip of the same material there has been inserted a strip of absorbent fibrous material, such as gauze, which has served to prevent direct contact between the two strips of aluminum, thus preventing shorting, and which, at the same time, has been used as a base for the electrolytic solution. In using this gauze, it has been absolutely necessary to remove substantially all traces of chlorine, thus materially increasing the expense of the final product. This gauze, has, of necessity, been of .a comparatively great thickness, thus increasing the amount of conducting solution used, and decreasing the efficiency of the condenser, since the electrical efflciency or power factor of the condenser is a function of the FR losses in the electrolyte. Furthermore, the electrical solution which has been heretofore used, has, of necessity, been of a comparatively high viscosity, thus further increasing the efllciency of the condenser, because the conductivity of an electrolytic solution varies inversely with the viscosity.

Under my present invention, I use a non-conducting crystalline structure, shown at 4, such as common sand or finely divided alumina, which has been passed through a mesh of from about 100 to 200, this sand serving to separate the strips 0 of aluminum or electrodes, 3. It is of course apparent that the finer the sand, the more efficient the condenser, provided of course that the electrodes are not placed soclose together so as to short.

On a strip of aluminum which has not been coated with the aluminum oxide, the cathode, I sprinkle a mixture of screened sand and an oxygen liberating compound, preferably in hydrated form, whose fusing point is below the melting point of the aluminum used in the plates. I have I found that ammonium perborate is peculiarly well suited for this purpose. After this mixture has been sprinkled on the aluminum strip, so as to cover the strip with a thin layer thereof, I pass the strip through a furnace, heating it to a 10 temperature at which the ammonium perborate will fuse, liberating its water of crystallization, and forming a film-like coating in which the sand is embedded and aflixed to the aluminum strip. I then apply to this strip, as treated, a film-like ll conducting solution, such as a mixture of ammonium borate and ethylene glycol, the ammonium borate constituting about 10% to 60% of the solution, by weight. I then place this strip in juxtaposition to the strip coated with the 20.

aluminum oxide, and assemble in the usual manner, 5 and 6 showing the terminals of the condenser in assembled form.

I have found that by using this crystalline. material, I have been enabled greatly to de-' 25 crease the space between the two aluminum strips, without fear or danger of shorting", and, at the same time, it has been possible to use a. much less viscous conducting solution, without the likelihood of the fluid running off in sub- 30 sequent operation and use.

While I do not wish to be bound by my present explanation of why I am enabled to use a thinner solution, I believe that the film-like coating of fused ammonium perborate absorbs some por- 35 tion at least of the solution, preventing it from running on.

Since it is apparent that the efficiency of a condenser varies inversely with the amount of conducting solution between the plates per unit area of plate surface, one advantage of my present invention is obvious. Furthermore, because of the fact that the conducting solution will not run off, even though comparatively thin, I am enabled to use a conducting solution of optimum viscosity, that is, that viscosity at which the solution offers the least resistance to the passage of an electric current. Furthermore, since the losses which result in a condenser of lessened efflciency are transmute'd largely into heat, which heat tends to decrease the resistance of, and finally break down the coating of aluminum oxide,

a further advantage of my present invention is the longer life of a condenser made in accordance therewith. 6o

This completes the description of the illustrative embodiment of the present invention.

, stead of sand or alumina, I can use any finely divided highly insulating crystal.

What I claim as my invention'is:

1. An electrolytic condenser composed of a plurality of electrodes, at least one of which is film-forming, said electrodes being separated by finely divided non-conducting crystals amxed to one of the electrodes.

2. An electrolytic condenser composed of a plurality of electrodes, at least one of which is film-forming, said electrodes being separated by finely divided non-conducting crystals which are fused to one of the electrodes by an oxygen liberating compound.

3. An electrolytic condenser composed of a plurality of electrodes, at least one of which is film-forming, said electrodes being separated by finely divided sand aflixed to one of the electrodes.

4. An electrolytic condenser composed of a plurality of electrodes, at least one of which is film-forming, said electrodes being separated by finely divided sand which is fused to one of the electrodes by ammonium perborate.

5. An electrolytic condenser, composed of a plurality of electrodes, at least one of which is film forming, said electrodes being separated by finely divided non-conducting crystals which are embedded in a fused salt amxed to one of the electrodes.

6. In an electrolytic condenser composed of a plurality of electrodes, at least one of which is film-forming, an electrode, the surface of which is provided with finely divided non-conducting crystals which are embedded in a fused salt amxed to one of the electrodes.

7. In an electrolytic condenser composed of a plurality of electrodes, at least one of which is film-forming, an electrode, the surface of which is provided with finely divided non-conducting crystals which are embedded in a fused oxygen liberating compound affixed to one of the electrodes.

8. In the process of making an electrolytic condenser, the steps of applying finely divided nonconducting crystals and an oxygen liberating compound to one of the electrodes, and thereafter fusing said oxygen liberating compound so that the finely divided non-conducting crystals are embedded in the resulting fused oxygen liberating compound.

9. In the process of making an electrolytic condenser, the steps of applying finely divided sand and an oxygen liberating compound to one of the electrodes, and thereafter fusing said oxygen liberating compound so that the finely divided sand is embedded in the resulting fused oxygen liberating compound.

10. In the process of making an electrolytic condenser, the steps of applying finely divided non-conducting crystals and ammonium -perborate to one of the electrodes, and thereafter fusing said ammonium perborate so that the finely divided non-conducting crystals are embedded in' the resulting fused ammonium-perborate.

11. In the process of making an electrolytic condenser, the steps of applying finely divided sand and ammonium perborate to one of the electrodes, and thereafter fusing said ammonium perborate so that the finely divided sand is emborate.

12. In the process of making an electrolytic condenser, the steps of applying finely divided non-conducting crystals, and an oxygen liberating compound whose fusing point is lower than the melting point of the electrodes, to one of the electrodes, and thereafter fusing said oxygen liberating compound so that the finely divided non-conducting crystals are embedded in the resulting fused oxygen liberating compound.

ARNOLD RADIES. 

